The Invisible Light

A field guide to radio — light your eyes can't see — with live demonstrations of waves and signals, and the story of Maxwell, Hertz and Marconi, who predicted it, proved it and put it to work.

It exists because radio is everywhere and almost nobody can say what it is. Music, voice notes, GPS and your neighbour's Wi-Fi are all the same thing at different frequencies.

What to take from it: radio isn't a mysterious signal in the air. It's light — and once you see it that way, the rest of the technology falls into place.